单细胞RNA测序解析肺组织炎症中ILC2s的异质性和PD-1调控ILC2s活性的分子机制

Asthma is a common airway inflammatory disease of the respiratory system. At present, there are estimated 300 million people suffering from asthma worldwide, and its prevalence is increasing year by year. Overproduction of interleukin-4 (IL-4), IL-5 and IL-13 is the key factor leading to a series of pathological changes in asthma. Type Ⅱ innate lymphoid cells (ILC2s) are the main source of these cytokines and play an irreplaceable role in the pathogenesis of asthma. However, the mechanism of activation of ILC2s in lung tissue and the mechanism of its activity regulation are unclear. Here, we will carry out the following studies on the basis of the previous work: 1) the use of single-cell RNA-sequencing to characterize the functional ILC2s subsets in lung inflammation; 2) the combination of single-cell RNA-sequencing and cell adaptive transfer in vivo experiments to reveal ILC2s activation pathway and molecular mechanisms; 3) The use of genetically modified mouse model and RNA-sequencing technology to clarify the function of PD-1 during lung ILC2s activation and its molecular mechanism. The above studies will reveal the pathogenesis of asthma caused by ILC2s activation and provide a scientific basis for targeted treatment strategy for asthma.

哮喘是一种常见的呼吸系统炎症性疾病。目前全球约有3亿哮喘患者，且发病率呈逐年上升趋势。白介素-4（IL-4）、IL-5和IL-13过度分泌是导致哮喘一系列病理变化的核心因素，Ⅱ型固有淋巴细胞（ILC2s）作为这些细胞因子的主要来源，在哮喘的发病过程中发挥着不可替代的作用。目前，肺组织ILC2s活化的机制及其活性调控的机理尚不明确。本项目将在前期工作基础上开展如下研究：1）利用单细胞RNA测序解析气道炎症条件下肺组织ILC2s的亚群构成及其功能；2）结合单细胞RNA测序与细胞体内移植等方法揭示ILC2s活化途径和分子机制；3）利用基因修饰小鼠模型与RNA测序技术阐明PD-1在肺组织ILC2s活化中的功能及其调控的分子机制。上述研究将进一步揭示哮喘发病的机制，并为哮喘的靶向治疗提供科学依据。

Ⅱ型天然淋巴样细胞（ILC2）是天然淋巴样细胞家族成员，广泛分布于气道、皮肤、肠道和泌尿生殖道等黏膜组织中，维持其稳态。ILC2细胞功能失调涉及多种疾病，包括过敏性鼻炎、哮喘和皮炎。在该国家自然科学基金项目的资助下，本项目针对肺组织ILC2的异质性和活化机制进行了研究，利用单细胞转录组测序、基因报告小鼠和基因敲除小鼠等技术，圆满完成了计划书中的研究内容与任务。. 本项目取得的主要研究成果如下：1）发现气道炎症条件下小鼠肺组织ILC2由2个非活化ILC2亚群和2个活化的ILC2亚群构成； 2）转录因子Nr4a1标志着一个特殊的ILC2活化亚群，这个亚群既表达组织驻留记忆T细胞的分子特征，也表达效应记忆T细胞和中央记忆T细胞的分子特征，而且这群细胞表达更高水平的增殖、激活和创伤修复相关基因； 3）还发现这群Nr4a1+ILC2受到免疫抑制分子PD-1的调控，PD-1的缺失导致初始状态的ILC2以不同的路径分化为Nr4a1+ILC2，PD-1缺失的ILC2具有更强的增殖能力。上述研究为进一步开发PD-1分子和ILC2细胞治疗炎症相关疾病提供了重要理论依据，有助于开发新的治疗干预措施。